Document handling apparatus is presently available and is in widespread use for performing operations such as counting and endorsing sheets continuously at high speed and without interruption such as, for example, counting sheets, food stamps, coupons, checks and the like and cancelling items such as, for example, checks, food stamps, coupons and the like. These operations generally lend themselves to being performed continuously at high speed and without interruption. Equipment suitable for performing the aforesaid operations is described, for example, in U.S. Pat. Nos. 3,771,783 issued Nov. 13, 1973 and U.S. Pat. No. 3,944,210 issued Mar. 16, 1976, both of which patents are assigned to the assignee of the present invention. The apparatus described in these patents teaches a technique for receiving a stack of sheets in an infeed hopper, moving the sheets in a single file fashion past a counting and/or endorsing station and thereafter stacking the counted and/or endorsed sheets in an output stacker. So long as documents are presented to the infeed hopper, the operation can be performed continuously and without interruption.
However, the requirements within the area of document handling make it extremely advantageous to be able to examine documents and sort them according to certain criteria such as genuine or suspect; clean or dirty; too stiff or too limp (typically due to extensive use and handling); having perforations or cuts; having torn or folded corners; and the like. Equipment presently available for handling and examining documents typically is designed to continuously and without interruption, feed and stack sheets meeting certain criteria for acceptable documents and to halt the sheet feeding operation upon the examination of a sheet failing to meet the criteria for acceptability and to cause the last sheet fed to the output stacker to be the unfit sheet. Assuming that the number of unfit sheets per total number of examined sheets is quite small, say one per thousand or one per five thousand, interruptions of this nature are quite insignificant. However, in the event that the sheets being examined alternate between fit and unfit status, for example, the number of interruptions in the document feeding process of the above mentioned design is excessive, rendering the equipment totally impractical for use. Manual performance of the examination procedure is an alternative to present-day equipment, but is impractical due to the fact that the operation is quite slow and quite tedious.